1. Field of the Invention
The present invention relates to a data storage device, and more particularly, to a head parking ramp for a data storage device to stably park a read/write head when the operation of the data storage device stops.
2. Description of Related Art
A hard disk drive (HDD), which is one of data storage devices used for computers, reproduces data stored on a disk or records data on the disk using a read/write head. In the HDD, to perform the above functions, the head is moved to a desired position by an actuator by being lifted to a specified height from a recording surface of a rotating disk.
When the HDD is not in operation, that is, when the disk is not rotating, the head is parked at a position out of the recording surface of the disk to prevent the head from colliding against the recording surface of the disk. Such a head parking system can be classified into a contact start stop (CSS) method and a ramp loading method. In the CSS method, a parking zone where data is not recorded is provided in an inner circumferential area of the disk and the head contacts the parking zone and is parked thereon. In the ramp loading method, a ramp is located outside the disk and the head is parked on the ramp.
According to the CSS method, since the head contacts the parking zone and parked thereon, when an impact is applied to the disk when the disk drive is not in operation, that is, the disk is not rotating, the disk and the head collide with each other as a result of the impact. Accordingly, the head is damaged so that a read/write performance of the head is considerably deteriorated.
Thus, for a portable hard disk drive, for example, a mobile disk drive using a 2.5″, 1″, or 0.85″ disk, a ramp loading type head parking system is widely adopted, in which the head is parked on a ramp separated from the disk when the disk drive does not operate so that a damage to the head due to collision between the disk and head is prevented,
FIG. 1 is a plan view illustrating a hard disk drive adopting a conventional ramp loading type head parking system. FIG. 2 is a magnified perspective view illustrating the head parking ramp of FIG. 1. FIG. 3 is a side view illustrating the ramp of FIG. 2.
Referring FIGS. 1 through 3, the hard disk drive includes a spindle motor 12 installed on a base member 10, at least one disk 20 installed on the spindle motor 12, and an actuator 30 moving a slider 35 having a read/write head for reproduction and recording of data to a specified position on the disk 20. The actuator 30 includes a swing arm 32 rotatably coupled to a pivot 31 installed on the base member 10, and a suspension 33 installed at an end portion of the swing arm 32 and supporting the slider 35 having the head to be elastically biased toward a surface of the disk 20. The slider 35 in a state of being attached to a flexure 34 is supported by the suspension 33.
A voice coil motor (VCM) to rotate the swing arm 32 is provided at the actuator 30. The VCM includes a VCM coil 37 coupled to the other end portion of the swing arm 32 and a magnet 38 arranged to face the VCM coil 37. The VCM configured as above is controlled by a servo control system and rotates the swing arm 32 in a direction following the Fleming's left hand rule by interaction between current applied to the VCM coil 37 and a magnetic field formed by a magnet 38. When the power of the hard disk drive is on and the disk 20 starts to rotate in a direction D, the VCM rotates the swing arm 32 counterclockwise in a direction A so that the slider 35 having the head moves to the recording surface of the disk 20. The slider 35 is lifted to a specified height from the surface of the disk 20 by a lift force generated by the disk 20 that is rotating. In this state, the head mounted on the slider 35 performs a function of reproducing or recording data with respect to the recording surface of the disk 20.
When the hard disk drive is not in operation, that is, when the disk 20 stops rotating, the head is parked at a position out of the recording surface of the disk 20 so as not to collide the recording surface of the disk 20. To this end, a ramp 40 is installed outside the disk 20 and an end-tab 36 supported by the ramp 40 is provided at an end portion of the suspension 33.
The ramp 40 includes a fixed portion 41 fixed to the base member 10 and a support portion 42 extending from the fixed portion 41 toward the disk 20 and having a support surface 43 supporting the end-tab 36 by overlapping each of the upper surface and the lower surface of the outer circumferential portion of the disk 20. The end portion of the support surface 43 close to the disk 20 is inclined so that loading and unloading of the end-tab 36 are smoothly performed. The end-tab 36 typically bulges toward the support surface 43 to reduce a contact area with respect to the support surface 43 of the ramp 40.
When the head is parked on the ramp 40, the actuator 30 is arbitrarily rotated by an external impact or vibration applied to the disk drive so that the head can escape from the ramp 40 and move to the recording surface of the disk 20. In this case, since the head contacts the recording surface of the disk 20, the head and the recording surface of the disk 20 can be damaged. Thus, in a state in which the disk 20 stops rotation and the head is parked on the ramp 40, to prevent the actuator 30 from rotating arbitrarily, an actuator latch 50 is provided to lock the actuator 30 at a particular position.
In the ramp loading type head disk drive configured as above, when an external impact is received, vibration is generated in the disk 20. When the impact applied to the disk 20 is relatively strong, as shown in FIG. 3, the disk 20 vibrates up and down and the upper and lower surfaces of the outer circumstantial portion of the disk 20 contact a disk facing surface 44 of the support portion 42 of the ramp 40. As a result, the data recording surface of the disk 20 and data recorded on the recording surface are damaged.
FIG. 4 shows a ramp for head parking which is disclosed in Japanese Patent Publication No. 2002-279744. Referring to FIG. 4, a support portion 62 of a ramp 60 includes a support surface 63 supporting a read/write head and a disk facing surface 64 facing the disk 20. The disk facing surface 64 is inclined. When the disk 20 vibrates due to an external impact, an edge portion of the disk 20 first contacts the disk facing surface 64 so that the recording surface of the disk 20 does not contact the disk facing surface 64. Thus, a problem that the recording surface of the disk 20 is damaged by colliding against the disk facing surface 64 is prevented.
However, when the disk 20 collides against the disk facing surface 64 of the support portion 62, an impact is applied to the support portion 62 that is relatively thin. When such an impact is repeated, the support portion 62 can be deformed so that the head loading/unloading function of the support portion 62 is deteriorated.